Thread veins, sometimes called spider veins, are enlarged visible vessels that commonly appear on the face and legs. They are red, purple, or blue blood veins that twist and twirl just beneath the surface of the skin. When on the face, you can find them around the nose, cheeks, and chin. Long-term skin inflammation, acne, hormones, sun exposure, trauma, alcohol, and medicine cause thread veins to overgrow and serve no beneficial role for the skin.